Is Perception Reality? Anticipated Pain Levels Affect Outcomes in Cutaneous Cancer Removal

Patients undergoing cutaneous cancer removal surgery who expect to sustain a significant amount of pain are more likely to experience higher pain levels during local anesthetic injection, but the addition of vibration during injection may help, according to a recently published randomized trial.

“Vibration has been shown to decrease injection site pain in patients; however, to date, this effect has not been assessed for patients who catastrophize pain (ie, patients who anticipate a higher pain level),” wrote the study authors, whose work appeared in JAMA Facial Plastic Surgery. “The anticipation of a pain score greater than 4 on the 11-point Numeric Rating Scale (NRS) has been associated with an increase in a patient’s perception of procedural pain.”

The study, which took place at a tertiary dermatologic surgery clinic between June 19 and Sept. 4, 2018, compared patients who catastrophize pain (NRS score > 4) to those who do not (NRS score ≤ 4). Patients described their baseline and anticipated pain levels, as well as drug use. A vibratory anesthetic device (VAD) was used on the treatment site prior to anesthetic injection (VAD ON) or off (VAD OFF) mode. The primary outcome was pain, as reported using the 11-point NRS; 0 indicated “no pain,” and 11 indicated “the worst pain imaginable.” The minimum clinically important difference was defined as 22% or more, and the substantial clinically important difference was defined as 57% or more; these cutoffs evaluated how vibration impacted patient-reported NRS score during anesthetic injection (iNRS score).

Feeling Is Believing

Final analysis included 87 patients and 101 reported unique events, of which 64 were reported in men and 37 in women. In patients who catastrophized pain, the mean iNRS score was 2.27 (confidence level [CL] 0.66), compared to 1.44 (CL 0.39) among patients who did not catastrophize pain (P = 0.03). Among the total cohort, VAD ON was associated with a 38.9% decrease in mean iNRS score compared to VAD OFF (1.24 [CL 0.38] vs. 2.04 [CL 0.54]). In patients who catastrophized pain, a 25.5% decrease in mean iNRS score was observed with VAD ON versus VAD OFF (1.91 [CL 0.99] vs. 2.57 [CL 0.98]); in patients who did not catastrophize pain, there was a 79.4% decrease (1.02 [CL 0.40] vs. 1.84 [0.66], respectively). The only variable that significantly affected iNRS score was VAD ON, the researchers noted.

The study authors wrote in their abstract, “This trial demonstrates that those who catastrophize pain prior to a procedure report a higher perceived level of pain. The application of vibration during local anesthetic injection resulted in a minimum clinically important difference in pain level for patients who catastrophize pain and a substantial clinically important difference in pain level for patients who do not.”